What is the BMR for a 42-year-old woman?

The estimated BMR (basal metabolic rate) for a 42-year-old woman of average height and weight is 1381 kcal/day, calculated using the Mifflin-St Jeor equation.

Calorie Guide · Age 42

Calories for a 42-Year-Old Woman

Q: How many calories does a 42-year-old woman need?

A lightly active 42-year-old woman of average weight and height needs approximately 1899 kcal/day to maintain weight. Sedentary needs are around 1657 kcal, and very active around 2382 kcal.

Q: How many calories should a 42-year-old woman eat to lose weight?

A 42-year-old woman should eat approximately 1399 kcal/day to lose about 0.5 kg (1 lb) per week. This is a 500 kcal deficit from the estimated maintenance of 1899 kcal.

BMR, TDEE and exact calorie targets for weight loss, maintenance and muscle gain at age 42.

Calorie Needs at Age 42 — Average Woman

1381

BMR (at rest)

1657

Sedentary TDEE

1899
Lightly active TDEE

2141

Moderately active

1399

Weight loss target

1899

Maintenance

2199

Muscle gain target

How Many Calories Does a 42-Year-Old Woman Need?

Using the Mifflin-St Jeor equation with average US height and weight for a woman aged 42, the resting metabolic rate (BMR) is approximately 1381 kcal/day. With typical daily activity included, total calorie expenditure (TDEE) ranges from 1657 kcal (sedentary) to 2382 kcal (very active).

Age 42 note: Metabolism begins slowing ~1–2% per decade after 30. Maintaining muscle through resistance training and adequate protein (0.7–1 g/lb) offsets most of this decline.

Calorie Targets by Goal

Goal	Daily Calories	Expected Result
🔵 Aggressive weight loss	1149 kcal	~0.75 kg/week
📉 Weight loss	1399 kcal	~0.5 kg/week
✅ Maintenance	1899 kcal	Weight stable
💪 Lean bulk	2199 kcal	~0.25 kg/week
🏋️ Aggressive bulk	2399 kcal	~0.5 kg/week

Calorie Needs by Activity Level

Activity Level	Description	Daily Calories
Sedentary	Desk job, minimal movement	1657 kcal
Lightly active	1–3 workouts/week	1899 kcal
Moderately active	3–5 workouts/week	2141 kcal
Very active	Hard training 6–7 days/week	2382 kcal

How Metabolism Changes Around Age 42

Metabolic rate declines approximately 1–2% per decade after age 30, driven primarily by muscle loss (sarcopenia) rather than any inherent slowdown. At age 42, your BMR of 1381 kcal reflects your current muscle mass, height and hormonal status. The single most effective way to maintain or raise your BMR is resistance training — each kilogram of lean muscle burns roughly 13 kcal/day at rest.

Age	Estimated BMR (woman)	Change vs age 42
32	1431 kcal	+50 kcal
37	1406 kcal	+25 kcal
42	1381 kcal	—
47	1356 kcal	-25 kcal
52	1331 kcal	-50 kcal

Macronutrient Split at 1899 kcal

Macro	% of Calories	Grams/day	Calories
Protein	30%	142 g	568 kcal
Carbohydrates	40%	190 g	760 kcal
Fat	30%	63 g	567 kcal

At age 42, protein intake is especially important. Aim for at least 60–74 g/day to maintain muscle mass, whether you're in a deficit, at maintenance, or in a surplus.

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Frequently Asked Questions

How many calories does a 42-year-old woman need per day?A lightly active 42-year-old woman of average size needs approximately 1899 kcal/day to maintain weight. This ranges from 1657 kcal (sedentary) to 2382 kcal (very active).

How many calories should a 42-year-old woman eat to lose weight?Aim for 1399 kcal/day — a 500 kcal deficit from the 1899 kcal maintenance estimate — to lose approximately 0.5 kg per week. Never go below 1200 kcal (women) or 1500 kcal (men) for extended periods.

Does age 42 affect how many calories you burn?Yes. Every decade after 30, BMR drops ~1–2% mainly due to muscle loss. At age 42 the estimated BMR is 1381 kcal — compare to 1441 kcal at age 30. Resistance training largely offsets this decline.

Related Age Guides

Sources

WHO CDC Mifflin-St Jeor (PubMed)